Lava Covers Up Evidence of Water on Mars

New high resolution images gathered by the Mars Reconnaissance Orbiter spacecraft has shown that certain areas of the Martian landscape that seemed to have experienced disastrous flooding in the past may have been covered by lava flows. The Mars Reconnaissance Orbiter spacecraft orbited the red planet last March 2006 and produced the images were the result of three months of survey of the spacecraft. According to researchers, the images suggest that it would be harder for future landing missions on Mars to analyze any evidence of past water on the planet.

Athabasca Valles is a valley system on the Red Planet which scientists long thought to have been carved out by sudden, catastrophic flooding, was one of the areas surveyed by the Mars Reconnaissance Orbiter and the images from the spacecraft showed that the entire region looks like it is covered by a few meters of lava. Alfred McEwen, one of the researchers studying the images, still thinks that the Athabasca Valles was formed by flowing water, however based on the images, he said that future robotic missions to Mars may not be able to investigate the water's effect on the surface of the valley due to the lava.

Other images by the Mars Reconnaissance Orbiter seem to disprove some theories researchers have had about the Martian landscape. One such theory was with regards to the Red Planet's northern plains which scientists have long interpreted to be the remaining basin an ancient ocean. Images by the Mars Reconnaissance Orbiter showed that instead of being covered by a deep layer of fine sediments as some expected, the flat northern plains were instead strewn by large boulders which, if the plains were an ancient basin, should have been buried under layers of sediment long ago if the ocean had been deep, long-lived and turbulent. These findings suggests that it would be difficult to interpret the role water has played on the surface of Mars.

McEwen however said that the theoretical models might be wrong and that it is still possible that an ocean once covered the northern plain. In New Scientists' interview with McEwen, he said that there are a lot of theories of how Mars' oceans were formed and that some evidence of the oceans may be buried under the lava.

The observations by the Mars Reconnaissance Orbiter does not end the search for the role water played in the planet's past. According to Maria Zuber at MIT in Cambridge, there are a lot of evidence that water played a role in the planet's past and that these evidence remains in the poles and frozen in the ground. The observations by the MRO just suggests that some areas wherein water might have possibly flowed, were covered up by volcanic activity.

SOURCE:

David L. Chandler, Lava may have buried signs of Mars water. NewScientist.Com